|Title of Invention||
DRAWN POLYESTER YARN
|Abstract||Drawn polyester yarn of enhanced strength and improved adhesion properties for reinforcement of elastic structures, such as tires, conveyor belts and the like, is obtained on treatment, prior to drawing, with a lowwater fiber finish comprising an adhesion-promoting substance comprising a halogenated polyether containing at least one 2-halomethyloxyethylene unit and a 2,3-dihydroxypropyl end group.|
Hoechst-Trevira Gmbtt&-COf KG ^07/T 003
Xlmwiij>Qlyestec.yarn-iorjei.nforcemfint of elastic structures
This invention relates to drawn polyester yarn of enhanced strength and improved adhesion properties which is useful for reinforcing elastic
structures such as tires, conveyor belts and the like. j
Elastic structures such as tires, conveyor belts and the like have long been reinforced using yarns made of a wide variety of materials. Initially, the reinforcements used were made of rayon and polyamide, but over time polyester fiber became more and more important, too. To improve the suitability of polyester fiber for use as reinforcing material, both the fiber itself and the adhesive material have been further developed. For instance, the hydrolysis resistance of polyethylene terephthalate has been improved by increasing the molecular weight and reducing the carboxyl end group content. Yarn strength improved as spinning and drawing technology improved.
The adhesion between the yarn material and the elastic material such as rubber, Caoutchouc, etc..improved as the result of the development of a whole series of dip systems. Many known adhesives are based on epoxy compounds, as described for example in U.S. Patent 3,793,425 and in U.S Patent 4,044,189. U.S. Patent 4,438,178, for example, teaches ethers or esters based on epichlorohydrin and polyhydric alcohols or polycarboxylic acids. These compounds again contain epoxy groups.
Adhesives without epoxy groups are a recent development. For instance, EP-A1-0 637 602 discloses organic compounds containing 2-halomethyl-oxyethylene units, secondary hydroxyl groups, and ester groups derived
from organic acids. These compounds are essentially free of halohydrin and epoxy groups and are used, for example, for improving the adhesion of fibers composed of polyamides, polyesters, carbon, etc.
EP-A2-0 395 432, finally, describes polyethers which contain at least one 2-halomethyloxyethylene unit and a 2,3-dihydroxypropyl end group and which are likewise essentially free of epoxy groups and halohydrin groups. The aforementioned compounds which are free of epoxy and halohydrin groups are applied to the fibers to be treated as aqueous emulsions or aqueous solutions having a considerable water content.
Japanese Kokai 7-70819 describes a process for drawing undrawn polyester yarn spun at high speed wherein the yarn is taken off and treated before drawing with an oily fiber finish having a water content of not more than 10%. The yarn is then subjected to multistage drawing at different temperatures. The yarn thus produced can be used, for example, in the form of a cord for reinforcing rubber articles.
This Japanese patent application does not teach the improved adherence to rubber, and the strengths obtained are below those achieved according to the present invention. Nor does said reference motivate one skilled in the art in any way to use compounds as adhesion improvers, as is the case with the present invention.
Although numerous ways are known to produce polyester yarn having good mechanical properties and then to provide it with adhesives to improve adhesion between the fiber and the elastic material, there continues to be a need for polyester yarn which has improved mechanical properties and good adherence to the elastic material. It is, therefore, an object of the present invention to provide a polyester yarn which has enhanced strength and improved adhesion properties in the reinforcement of elastic structures such as tires, conveyor belts and the like and which is
simple and economical to produce and whose process of production is toxicologically safe.
This object is achieved by drawn polyester yarn of enhanced strength and
improved adhesion properties for reinforcement of elastic structures such as tires, conveyor belts and the like, said yarn having applied to it prior'to the drawing process a fiber finish which has a low water content and which comprises an adhesion-promoting substance comprising a halogenated polyether which contains at least one 2-halomethyloxyethylene unit and a 2,3-dihydroxypropyl end group and which is essentially free of epoxy . groups and halohydrin groups and optionally further comprising customary additives such as lubricants, surfactants and/or antistats.
Further advantageous embodiments are recited in claims 2 to 7.
The present invention further provides a process for producing such polyester yarn as per claim 8, the use of the yarn for reinforcing elastic structures as per claim 9 and a fiber finish composition for application to polyester yarn prior to drawing; for example in the course of the spin-draw process.
The adhesion-promoting substances providing access to the spin-drawn polyester yarn of the invention are known per se and are described, for example, in EP-A2-0 395 432. The disclosure content of this European patent application is expressly incorporated herein by reference.
The adhesion-promoting substances applied to the polyester yarn can be represented by the following chemical.formula:
where R is a radical of an etherified organic polyhydroxy compound, n is from 2 to 8 and indicates the number of ether chains emanating from R, m is from 1 to 7, and y denotes chlorine, bromine or iodine or a mixture thereof.
It is not necessary for all the hydroxyl groups of the etherified organic polyhydroxy compounds to be etherified. It is perfectly possible, when j glycerol is the polyhydroxy compound, for only two of the hydroxyl groups to be etherified and one free hydroxyl group still to be present. If, for example, sorbitol is the polyhydroxy compound, from one to four hydroxyl groups may remain unetherified without problems.
The applied adhesion-promoting substance is preferably derived from glycerol as polyhydroxy compound.
Adhesion promoters used according to the present invention which are derived from glycerol as preferred polyhydroxy compound may advantageously be substances of the formula II
The applied fiber finish, in addition to the adhesion-promoting substance, may comprise customary additives such as lubricants, surfactants and/or antistats, viscosity regulators, activators. It further comprises a small amount of water.
The fiber finish preferably consists of
A) a conventional base comprising A1) lubricants A2) surfactants and A3) antistats,
these constituents being in particular: A1) ester oil
A2) ethoxylated fatty acids and A3) organic phosphoric esters.
A further constituent is
B) a viscosity regulator (diluent), which is a dialkyl polyglycol ether in
Essential to the invention is
C) an adhesion-promoting substance as per the main claim and the
pertinent subclaims. It is preferably a hydrolyzed glycerol
In addition there is present
D) a rubber adhesion activator, especially a potassium salt of an
inorganic or organic acid, preferably potassium acetate.
A minimum amount of
is indispensable as solvent for D.
The proportions of the components of the fiber finish are generally as follows:
A) 85 to 20% by weight, preferably 58% by weight
B) 5 to 40% by weight, preferably 28% by weight
C) 4 to 25%- by weight, preferably 10% by weight
D) 0.5 to 2.5% by weight, preferably 1.0 to 3.0% by weight
E) 1.0 to 5.0% by weight, preferably 1.5 to 3.0% by weight
The substance C) used can be characterized by the structural formula
The high strength filaments produced using the fiber finish of the invention are characterized by the following data:
tenacity > 80.0 cN/dtex, preferably > 82.0 cN/dtex, coupled with an elongation at break of 10 to 12%, preferably 11%, and a 200°C hot air shrinkage of not more than 14%.
A fiber finish is prepared from:
A) 58% by weight of the commercial product AFILAN TEF from Hoechst AG
B) 28% by weight of the commercial product SYNTHACID 383 from Dr. Bohme KG
C) 10% by weight of the commercial product LUBRIL 17040 from Rhone-Poulenc
D) 1.3% by weight of potassium acetate, and
E) 2.7% of water.
A solution is prepared from 1.3 kg of potassium acetate and 2.7 kg of
demineralized water. A stirred tank is charged with 28.0 kg of Synthacid
383, and 4.0 kg of the potassium acetate solution prepared are stirred in.
Subsequently the weighed-out amount of 10.0 kg of Lubril 17040 is added
to the Synthacid mixture, which is followed by stirring for about 60 min until
the product is fully homogenized.
Thereafter 58.0 kg of Afilan TEF are mixed in. The total mixture is ; i
subsequently stirred for 30 min.
A high strength filament yarn was produced from polyethylene terephthalate on a spin-draw machine with two-stage drawing using this fiber finish, under the following conditions:
Nominal linear density dtex 1100
Filament count 200
Spinning takeoff m/min 2500
Speed Inlet duo m/min 408
Duo 1 m/min 412
Duo 2 m/min 1448
Duo 3 m/min 2541
Duo 4 m/min 2541
Draw ratio 1:6.23
Temperatures Duo 1 °C 115
Duo 2 °C 125
Duo 3 °C 233
Duo 4 °C 120
Fiber finish add-on
in % by weight on
weight of yarn % 0.52
The following yarn parameters were obtained;
DIN EN ISO 2062 breaking force N 94.7
DIN EN ISO 2062 tenacity cN/tex 84.1
Elongation at break % 11.0
Extension at stated load (54 cN/tex) % 5.52
200°C hot air shrinkage % 14.0
Latex adhesion N/cm 244
Production of thread:
A 3 S130/Z130 thread is produced in 2 steps by ring spinning:
a) production of a single yarn twisted with 130 turns/m in the
b) production of the thread from 3 single yarns with 130 turns/m in the
The thread is given a rubber-friendly finish by means of a resorcinol-
formaldehyde-latex (RFL) dip. The dip is prepared from:
40 g of Bunatex VP 2210 (40% strength) from Huls AG 45 g of Penacolite B1-A (50% strength) from Inspec (USA) 12 ml of concentrated ammonia (about 25% strength) 18 ml of formaldehyde (about 30% strength) 510 ml of distilled water.
In one operation, the thread is dipped in the RFL bath, the dipped thread dried and the RFL resin curjed (230°C, 120 s) while at the same time the thread is tensilized (thread tension 700 cN).
Preparation of test specimen: >
The latexed thread is vulcanized into a standard rubber mixture composed of 100% of natural rubber and customary rubber additives (Hoechst AG). Rubber strips 10 mm x 300 mm in size and 3 mm in thickness are placed into a vulcanizing mold, and the thread is placed on top in a 30-fold parallel arrangement to leave about 20 mm rubber-free thread ends and covered over with rubber strips 6 mm in thickness.
Vulcanizing is effected in a hydraulic vulcanizing press from Wickert & Sohne at 143°C following preheating at 3 kN/cm2 for 45 min. The sample is then allowed to cool down and made ready for the test.
Determination of adhesion:
The adhesion test is carried out on a Zwick universal tester under the
Clamped length 140 mm
Rate of extension 300 mm/min
Number of tests 30
A specially fabricated upper clamp is used to hold the specimen without slippage. The free thread end is placed into the lower wrap clamp. The average value is reported as the latex adhesion.
(1) 4.5 % of BK 2104, an ester oil from Henkel KG
(2) 4.5 % of STANDOPOL 1100A, an emulsifier with antistat,
(3) 3.0 % of HOE T 1812, a further emulsifier, Hoechst AG
(4) 2.8% of LUBRIL 17040, Rhone-Poulenc
(5) 0.2 % of potassium bicarbonate
(6) 85.0% of water.
Components (1) to (4) are homogenized in succession at 50°C by stirring and then stirred for a further 30 min. Thereafter this full strength batch is adjusted to 15% with demineralized water and emulsified. KHC03 is added to the ready-prepared emulsion with stirring.
A yarn was produced with this fiber finish on the same spin-draw machine as mentioned above:
Nominal linear density dtex 1100
Filament count 200
Spinning takeoff m/min2100
Speed Inlet duo m/min 370
Duo 1 m/min 375
Duo 2 m/min 1293
Duo 3 m/min 2135
Duo 4 m/min 2102
Draw ratio ~ 1:5.76
Temperatures Duo 1 °C 115
Duo 2 °C 125
Duo 3 °C 233
Duo 4 °C 120
Fiber finish add-on % 0.55
The following yarn parameters were obtained:
DIN EN ISO 2062 breaking force N 84,0
DIN EN ISO 2062 tenacity cN/tex 75,0
Elongation at break % 14,2
Extension at stated load (54 cN/tex) % 7.2
200°C hot air shrinkage % 12.5
(according to DIN 53886 P3)
Latex adhesion N/cm 223
Owing to the poorer running properties with this aqueous fiber finish, this comparative yarn could not be produced with such high process settings I (takeoff speed, draw ratio).
Customary polyester yams, especially yarns based on polyethylene terephthalate, are suitable for application of a low water fiber finish as per
the invention prior to drawing. It in also possible to use yarns based on
copolyesters. Similarly, polyesters modified by additives can be used. POY is particularly suitable.
It is particularly surprising that the drawn polyester yarn of the invention has not only enhanced strength but also improved adhesion properties when a low water preparation of the adhesion-promoting substance is applied to it prior to drawing. Compared with drawn polyester yarn produced using an aqueous preparation, the strength is up by 12% and the adhesion by 10%.
The drawn polyester yarn of the invention is very economical to produce on high speed machinery as well. There are no toxicological problems. Production is very economical since it is not necessary to prepare emulsions.
What is claimed is:
1. Drawn polyester yarn of enhanced strength and improved adhesion properties for reinforcement of elastic structures such as tires, conveyor belts and the like, said yarn having applied to it prior to the drawing process a fiber finish which has a low water content and which comprises an adhesion-promoting substance comprising a halogenated polyether which contains at least one 2-halomethyl-oxyethylene unit and a 2,3-dihydroxypropyl end group and which is essentially free of epoxy groups and halohydrin groups and optionally further comprising customary additives such as lubricants, surfactants and/or antistats and the like.
2. The drawn pblyester yarn of claim 1, wherein the fiber finish which is applied has a water content of below 10% by weight, based on ttjie total weight of the fiber finish. !
3. The drawn polyester yarn of claim 2, wherein the water content of the fiber finish is fiber finish.
4. The drawn polyester yarn of one or more of claims 1 to 3, wherein the adhesion-proTnoting substance is applied as a solution in a polyglycol ether.
5. The drawn polyester yarn of one or more of claims 2 to 4, wherein the fiber finish which is applied comprises from 5 to 25% by weight, based on the total weight of the fiber finish, of the halogenated polyether.
6. The drawn polyester yarn of any one of claims 1 to 5, characterized by a tenacity of >80 cN/tex.
The drawn polyester yam of one or more of claims 1 to 6, produced by a spin-draw process.
A process for producing a polyester yarn as claimed in at least one of claims 1- to 7, which comprises applying to the yarn prior to drawing a fiber finish which has a low water content and which comprises an adhesion-promoting substance comprising a halogenated polyether which contains at least one 2-halomethyl-oxyethylene unit and a 2,3-dihydroxypropyl end group and which is essentially free of epoxy groups and halohydrin groups and optionally further comprising customary additives such as lubricants, surfactants and/or antistats and the like.
The use of the polyester yarn of at least one of claims 1 to 7 for reinforcement of elastic structures.
A fiber finish composition for application to polyester yarn prior to drawing, said fiber finish having a low water content and comprising an adhesion-promoting substance comprising a halogenated polyether which contains at least one 2-halomethyloxyethylene unit and a 2,3-dihydroxypropylene end group and which is essentially free of epoxy groups and halohydrin groups and optionally further comprising customary additives such as lubricants, surfactants ; and/or antistats and the like.
11. Drawn polyester yarn of enhanced strength and improved
adhesion properties for reinforcement of elastic structures
substantially as herein described and exemplified.
12. A process for producing a polyester yarn substantially as
herein described and exemplified.
|Indian Patent Application Number||102/MAS/1998|
|PG Journal Number||31/2007|
|Date of Filing||16-Jan-1998|
|Name of Patentee||INVISTA TECHNOLOGIES SARL|
|Applicant Address||TALSTRASSE 80, CH-8001 ZURICH.|
|PCT International Classification Number||C08J05/06|
|PCT International Application Number||N/A|
|PCT International Filing date|